No Module named PIL

Question

I know PIL is deprecated, so I installed Pillow instead, and for backward compatibility reason, Pillow is still using PIL as its module name. Here\'s my pip freeze look

Answer 1

I'm having this trouble too recently, so let me share my take on this. I'm on Mac OS X Mojave 10.14. I tried running the pip install pillow so many times blindly without finding deeper understanding as to where my python searches for its packages.

I encountered this error when I upgraded from OS X High Sierra to Mojave. My previously working Scrapy project just stopped running properly.

Note that I didn't use virtualenv.

First, you need to check which python is used by the system. In the Terminal, run

which -a python

You'll get something similar to this:

nicholass-mbp:~ nicholaslie$ which -a python /usr/local/bin/python /usr/local/bin/python /usr/bin/python

This leads me to searching inside the /usr/local/ folder. Turns out there's a folder to where my python is searching its packages, and that is inside /usr/local/lib/python2.7 (python) or /usr/local/lib/python3.7 (python3)

What my current pip install pillow do is installing the PIL package inside the /usr/local/lib/python2.7/site-packages directory, but not to /usr/local/lib/python3.7/site-packages

However, since my project uses Python 3, No module named PIL error simply tells you that the python3 instance you're using cannot find the PIL library.

I used Homebrew for managing my system packages such as node, python, etc. So what I did was reinstall python3 with Homebrew with:

brew reinstall python, then run pip3 install pillow.

Just ensure that the PIL package is installed properly in /usr/local/lib/python3.7/site-packages and you should be good to go. Hope this helps someone.